WPI APOLLO 4000, Instruction Manual

Page: 40 / 74

APOLLO 4000
NITRIC OXIDE DETECTION
WORLD PRECISION INSTRUMENTS C-16
brittle. The pressure regulator and tee purge adaptor should be stainless
steel. This is because nitric oxide is a corrosive gas.
3. Prepare 100 mL of a 10 % (by weight) KOH solution and place it in the
sidearm flask as illustrated above. The flask should be sealed with a stopper
through which the tubing passes by means of a Luer fitting to a syringe needle
which extends almost to the bottom of the flask. Tubing is used to connect the
side arm of the flask to the vial containing the water to be equilibrated with
NO. The KOH solution is used to remove other nitrogen oxides from the NO
gas.
4. Place 20 mL of distilled (preferably deionized) water in a small glass vial. Seal
the vial with a stopper and insert through the stopper a long syringe needle
which extends almost to the base of the vial. Connect this syringe needle to
the tubing from the KOH flask as illustrated. Insert an additional shorter
syringe needle which should not extend into the solution. This acts as
a pressure relief during purging.
Figure C5 —
Setup for preparing
a saturated NO
aqueous solution
must be in a fume
hood with forced
ventilation. Nitric
oxide is highly toxic
and, as illustrated,
escapes into the
atmosphere during
preparation of the
standards.
*Lecture bottle
of NO (14.2
liters, 98.5%)
obtained from
Aldrich, catalog
#29.556-6;
telephone 800-
558-9160